Hi!
I would like to ask for an opinion regarding my 13 inch MacBook Pro early 2011 model. The motherboard is a 820-2936 B revision.
The reason why it broke is pretty stupid, I just dropped a piece of aluminum tape on it while the back cover was off. It was not turned on but it had the battery plugged in so quite a few power rails were up and seems it still managed to short something out.
I have a green light with just the charger, if I connect the battery it charges correctly and the battery indicator on the side is working correctly displaying the charge level.
In SMC bypass mode the fan will come on at 100% but still no boot.
So I started a little bit of troubleshooting with the schematics and the boardview and I saw that the "ALL_SYS_PWRGD" is missing which is basically a prerequisite for getting in S0 state.
I then took each rail and measured it and as it turns out I am missing just "PPVCCSA_S0_CPU" so I concentrated on the IC generating it which is U7100 (ISL95870A).
It is getting supplied with voltage and is also getting an enable signal. First though was that the output is shorted somewhere but I read a little bit on the forum and the resistance to GND that I am getting on the output of the DC-DC converter is pretty consistent to some of the values I found here, which is about 14ohms.
I then took pin by pin and found some very low resistance values on the SREF, SET0 and SET1 pins of the IC:
Pin 7: SREF -> 3R
Pin 8: SET0 -> 0R
Pin 9: SET1 -> 8R
Trying to test the ESD diodes with the DMM on diode mode also bears similar results, 0 on all 3 pins.
I have also tested the 2 NMOS (Q7100) package with the DMM and it seems fine.
I am attaching a summary of the voltages I get on the main rails.
My opinion is that I should replace this IC but I kindly ask for you opinion as well: do you see any reason that this would come from a different problem and if so what should I order besides this DC to DC controller?
Many thanks in advance for reading this far!
I would like to ask for an opinion regarding my 13 inch MacBook Pro early 2011 model. The motherboard is a 820-2936 B revision.
The reason why it broke is pretty stupid, I just dropped a piece of aluminum tape on it while the back cover was off. It was not turned on but it had the battery plugged in so quite a few power rails were up and seems it still managed to short something out.
I have a green light with just the charger, if I connect the battery it charges correctly and the battery indicator on the side is working correctly displaying the charge level.
In SMC bypass mode the fan will come on at 100% but still no boot.
So I started a little bit of troubleshooting with the schematics and the boardview and I saw that the "ALL_SYS_PWRGD" is missing which is basically a prerequisite for getting in S0 state.
I then took each rail and measured it and as it turns out I am missing just "PPVCCSA_S0_CPU" so I concentrated on the IC generating it which is U7100 (ISL95870A).
It is getting supplied with voltage and is also getting an enable signal. First though was that the output is shorted somewhere but I read a little bit on the forum and the resistance to GND that I am getting on the output of the DC-DC converter is pretty consistent to some of the values I found here, which is about 14ohms.
I then took pin by pin and found some very low resistance values on the SREF, SET0 and SET1 pins of the IC:
Pin 7: SREF -> 3R
Pin 8: SET0 -> 0R
Pin 9: SET1 -> 8R
Trying to test the ESD diodes with the DMM on diode mode also bears similar results, 0 on all 3 pins.
I have also tested the 2 NMOS (Q7100) package with the DMM and it seems fine.
I am attaching a summary of the voltages I get on the main rails.
My opinion is that I should replace this IC but I kindly ask for you opinion as well: do you see any reason that this would come from a different problem and if so what should I order besides this DC to DC controller?
Many thanks in advance for reading this far!
